Lecture: Prof. Dr. Moritz Diehl
Tutor: Rachel Leuthold
The aim of this lecture course (6 ECTS) is that students understand the physical principles of wind energy and the technology of modern wind energy systems. It consists of lectures and exercises.
Contents:
- global wind energy resource
- aerodynamic principles of wind turbines
- design of modern wind turbines
- control of modern wind turbines
- the electrical system of wind turbines
- alternative concepts and airborne wind energy
Course Organization
The course is organized as a flipped classroom style course. We will provide recordings of lectures and suggest exercises to be completed, with a five-day block course of task-focused instruction. There will be office hours offered, for questions, discussions, or other help related to the course-work, once with Prof. Dr. Moritz Diehl, and twice with the tutor (Rachel). The detailed time plan is currently being developed.
This page is the course website, which will be kept maintained during the course to include any relevant information. A printable PDF version is available, with the main information set at the start of the course.
For other course-related questions, you are welcome to contact Rachel at [rachel.colette.leuthold at imtek.uni-freiburg dot de].
Sessions: This 6 ECTS course will be given as a block course, with five full days between: 28.7 - 1.8.2025 from 9:00 to 17:00 (mandatory), in a lecture hall in downtown Freiburg (HS 1016 (Kollegiengebäude I)), with preparatory meetings beforehand. The lectures on these days are planned to be fast, intense, and interactive!
The schedule of these preparatory meetings is as follows:
| April 23 | 08:30 - 09:55 | with Prof. Diehl | Orientation | (optional) |
| May 7 | 08:30 - 09:55 | with Prof. Diehl | Official Kick-Off | (mandatory) |
| May 21 | 08:30 - 09:55 | with Prof. Diehl | Official Follow-Up | (mandatory) |
| June 4 | 08:30 - 09:55 | with Rachel | Office Hours | (optional) |
| June 18 | 08:30 - 09:55 | with Rachel | Office Hours | (optional) |
| July 16 | 08:30 - 09:55 | with Prof. Diehl | Office Hours | (optional) |
These preparatory meetings will take place in room SR 00 007 (G.-Köhler-Allee 106).
Office hours: As included in the above table of preparatory meetings, there will be office hours with Prof. Diehl or the course tutor, where you can ask any questions about the course content. The format is meant to be highly interactive and depends strongly on your participation. We would recommend that while watching the video lectures or reading the course script, you write down any questions that come to your mind!
Resources:
- Lecture recordings: The lecture recordings were already created in a past semester.
- Course manuscript: The lectures are accompanied by a course manuscript, which you may find here.
- Wind Energy Handbook is available here.
- Wind Energy Explained: Theory, Design and Application is available here. This book should be your number one reference if you don't understanding something from the handbook.
Exercises: This course has two types of exercises:
First, there is a Mandatory Self-Assessment of Course Pre-Requisites that focuses on the most important course pre-requisite information in math and physics. This sheet will be given out on Wednesday May 7th, with the submission deadline (in the box outside Prof. Diehl's office, Building 102, Room 00-073) by 10am on Friday May 16th. To be eligible for the final exam, you must score at least 70% of the total points available in this exercise! You will receive the graded responses in class on Wednesday May 21st, to help you decide whether to proceed with the block course of 28.7 - 1.8.2025, and what subjects to refresh.
Furthermore, there are additional optional and ungraded exercises available. These additional exercises are voluntary (though, of course, we strongly recommend solving them). The solutions to the voluntary exercises are posted below, for self-correction.
Final evaluation: The entire grade for this course will be determined by the score of the final (written) exam. This final exam will be 'closed-book,' which means that ONLY pens, a calculator, and one A4 page (that is, two sides) of notes can be used. There will be no opportunity to consult computational resources like ChatGPT, Wolfram|Alpha, Python, etc. The questions will be partially multiple-choice and partially short-answer. There will be a date provided [TBD] to review your scored exam. The exam will be similar in style to this Practice_exam with solution Practice_exam_sol.
If you decide to follow the course, please make sure you register for both the Wind Energy Systems Exam and the Wind Energy Systems Studienleistung!
Schedule: The course will follow the below-listed subjects. Please note that self-study may be necessary to cover all the material, considering the time limitations imposed by the course's block-structure.
| Chapter | Content | Recordings | Exercises |
| Course Pre-requisites | |||
Chapter 1: Introduction | Section 1.1: Introduction (Slides) Section 1.2: Energy content of the wind Section 1.3: Power density of blade area Section 1.4: Components of modern wind turbine Section 1.5: Blade & Airfoil nomenclature | (optional exercise) | |
Chapter 2: The Wind Resource | Section 2.1: Origins Section 2.2: Global patterns Section 2.3: Mechanics of wind Section 2.4: Stable and unstable atmospheric stratification Section 2.5: Statistics of wind Section 2.6: Spectral properties of wind |
| (optional exercise) |
Chapter 3: Aerodynamics of Wind Turbines | Section 3.1: Wakes Section 3.2: Actuator disc model and the Betz' limit | (optional exercise) | |
Section 3.3: Wake rotation & rotor disc theory Section 3.4: Blade element momentum (BEM) theory | (optional exercise) | ||
Chapter 4: Mechanics & Dynamics of Wind Turbines | Section 4.1: Steady loads in normal operation Section 4.2: Stress and strain Section 4.3: Static beam bending Section 4.4.1: Intro: spring-mass-damper system Section 4.4.2: Eigenmodes Section 4.4.3: Rayleighs method Section 4.4.4: Dynamic beam equation Section 4.4.5: Tower eigenmodes Section 4.4.6: Stiff & soft towers Section 4.5: Blade oscillation & centrifugal stiffening | (optional exercise) | |
Chapter 5: Control of Wind Turbines | Section 5.1: Sensors and Actuators in wind turbines Section 5.2: Control system architecture Section 5.3: Control of variable speed turbines Section 5.4: Torque control at subrated power Section 5.5: Thrust jump at nominal wind speed |
| |
Chapter 6: Alternative Concepts | Section 6.1: Vertical axes wind turbines Section 6.2: Airborne Wind Turbines |
Special Events [TBD]
- A guided visit to the the E-138 turbine on Holzschlägermatte, Schauinsland, will be offered in the afternoon of 10.7.2025. The guided visit will be in English (either originally or via translation from German), and will be combined with a short hike to and from the turbine, each way between 45-90 minutes. Further details to follow.
- The University's Center for Renewable Energy (ZEE) is hosting a Renewable Energy Day on May 20, 2025, from 14:00 to 18:00, at the Auditorium of the University of Freiburg ”Aula, Kollegiengebäude 1“. More information is available here.
Links of interest
- Report on renewable power generation costs in 2018 (by IRENA) (PDF)
- Which way a wind turbine turns might not seem to matter (by the Economist) (screenshot)
- Atmospheric circulation patterns (from wikipedia)
- Article on the Global Energy Transition (by the Economist)
- Albert Betz: Wind-Energie. Cover, Turbine Illustrations, Concluding Sentence
